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The level crossing rate, the outage probability and the average time of fade duration of the Switch and Stay Combiner output signal, in the presence of Rice fading at the input, are determined in this paper. The results are shown graphically for different variance values, decision threshold values and signal and fading parameters values.
This paper presents a system for a location-based discovery of points of interest, based on the current geographic position of mobile users. The proposed approach exploits a mixture of Web 2.0 technologies (for the localization of point of interests), positioning techniques and cross-layer networking schemes for a seamless navigation, while moving through different and heterogeneous wireless networks.
In this work we investigate the performance of optical packet/burst switched (OPS/OBS) architectures connected as mesh and as ring topologies, for future optical metropolitan networks. Network throughput and protection to link failure under uniform traffic distribution for all nodes is investigated in order to evaluate the sensitivity of OPS/OBSN performance. Our results are based on analysis of simulations...
Unlike other wireless technologies, the deployment of 802.11 networks is not limited to operators: access points can easily be installed by end-users for domestic use. This singular type of deployment is the reason why 802.11 networks are omnipresent in our urban landscapes. Indeed, in metropolitan areas, laptops frequently detect tens of 802.11 access points from the same location. In this work,...
The paper suggests a software architecture to improve the accessibility to information from texts. This software combines techniques like: image processing, optical character recognition, machine translation, text analyze and text to speech. The application uses a scanner or a Web cam as an image input device, recognizes the text by using OCR, enables text translation by using Googlepsilas machine...
Fourth generation mobile systems and services will mainly be characterized by a horizontal communication model, where different access technologies such as cellular, cordless, wireless local area network, short-range connectivity, and wired systems will be combined on a common platform to complement each other optimally for different service requirements and radio environments. To access different...
Optical code division multiple access (OCDMA) systems, intensively investigated these last years, are known to suffer from multiple access interference (MAI). In addition, the photodetection process leads to beatings between the desired user information and the interferer ones, strongly degrading the system performance. To simplify the performance analysis, noise statistic is generally approximated...
Monitoring and measuring various metrics of high data rate and high capacity networks produces a vast amount of information over a long period of time. Characteristics such as throughput and delay are derived from packet level information and can be represented as time series signals. This paper looks at the Embedded Zero Tree algorithm, proposed by Shapiro, in order to compress computer network delay...
In a previous study we proposed a modified version of the recursive least-square (RLS) adaptive algorithm suitable for fixed-point implementation. Using an asymptotically unbiased estimator for the algorithm's cost function we reduced the dynamic range of this parameter. In this paper, we extend the procedure for the case of QR-decomposition-based least-squares lattice (QRD-LSL) adaptive algorithm,...
Short Message Service (SMS) has been one of the most popular services in mobile communication for years, and its usage is still growing. However, with the usage of Turkish character(s) in SMS message text, the maximum length of a single message reduces from 160 to 70 characters due to the transmission regulations of SMS designated by Cellular Telecommunications and Internet Association. This results...
Bluetooth, ultra-wideband (UWB), ZigBee, and Wi-Fi are four popular wireless standards for short-range communications. Specifically, ZigBee network is an emerging technology designed for low cost, low power consumption and low-rate wireless personal area networks (LR-WPAN) with a focus on the device-level communication for enabling the wireless sensor networks. In this paper, after a brief overview...
During emergency response to mass casualty disasters, one of the main logistic impediments faced by the On-site Organizational Chief (OOC) is to track the patients at the disaster site. We had proposed our previous work a new system based on a location aware wireless sensor network (WSN) to overcome these impediments and assist the responders in providing efficient emergency response. In this paper...
Recently, localization in wireless networks has gained a lot of interest; especially after some of the most interesting positioning application areas have emerged in wireless communications. The most important are the Federal Communications Commission (FCC) and the European Recommendation E112, both of which require that wireless providers should be able to locate within tens of meters users of emergency...
In this paper, the analytical modeling of a time-threshold based multi-guard bandwidth allocation scheme is presented using a two-dimensional Markov chain. The main idea of the scheme is based on monitoring the elapsed real time of handoff calls and according to a time threshold (te), a handoff call is either slightly-prioritized or fully-prioritized. A slightly-prioritized handoff call has higher...
Self similar behavior of the aggregate traffic is a well known issue in the networking area. In this paper, we first study the self similarity of the empirically aggregated VoIP traffic in a heterogeneous wireless network testbed environment and then model it using Fractional Gaussian Noise (fGn). The heterogeneity of the environment is provided by exploiting different wireless technologies in backbone...
In a VoIP (voice over Internet protocol) telephone system, we face the significant challenge of providing a teleconference feature that can support a large-scale teleconference without using excessive network bandwidth. This paper examines a new, bandwidth-efficient way of implementing a real-time VoIP teleconference system, and we present measurements of the improvements that we gained by refining...
As a system for guaranteeing Quality of Service of continuous media by traffic control, there exists Integrated Services using Resource ReSerVation Protocol that guarantees bandwidth for object traffics by executing bandwidth control. This system, however, restricts bandwidth for other traffics through the session of object traffics because of its static bandwidth control. Then, to solve the problem,...
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